ASA Monograph (3RD Edition) Chapter 12 · 13 yr old green 9 yr old green Materials and Methods 10 yr old green 12 yr old green As of 2009 0 10 20 30 40 50 60 70 80 90 100-1 1 357

2/22/2018

1

Understanding and Managing Organic Matter Accumulation in Cool-Season Putting Greens

Roch GaussoinUniversity of [email protected]

@rockinsince57

What do we want to learn today?

https://turf.unl.edu/

Then scrolldown

ASA Monograph (3RD Edition)

Chapter 12Characterization, Development, and Managementof Organic Matter in Turfgrass Systems

R.E. Gaussoin, Dep. of Agronomy and Horticulture, Univ. of NebraskaW.L. Berndt, Dep. of Resort and Hospitality Management,

Florida Gulf Coast UniversityC.A. Dockrell, Teagasc College of Amenity Horticulture

Dublin, IrelandR.A. Drijber, Dep. of Agronomy and Horticulture, Univ. of Nebraska

Organic matter development: Are We the Problem?

Or:

is organic matter % the green speed of the new millennium?

2/22/2018

2

How does organic matter accumulate?

Organic matter; defined

dead or near dead plant residue which accumulates in the grass ecosystem

How does organic matter accumulate?

As grasses mature there is a continual senescence of non or limited function parts (roots, shoots and leaves)

Senescence also happens when damage or injury occurs

How much OM is produced annually?

Roots = 3500 lbs/acre

Leaves = 2000 lbs/acre

Other = 2500 lbs/acre

TOTAL = 8000 lbs/acre

Fairway height blue/rye estimated annual production

8967 kg/ha

Where does organic matter accumulate?

Above ground Thatch/Mat

clipping residue

relatively short term

“pseudo” thatch

Below ground root zone

rhizosphere

Importance of (P)OM in the rhizosphere

deposition of particulate OM

microbial niches

nutrient uptake

pathogen competition

Factors influencing rootzone (P)OM accumulation

Mowing increase height=increase rooting

Irrigation root growth restricted in waterlogged soils

Cultivation increase or decrease

Fertility increase or decrease

Stress

2/22/2018

3

Rootzone accumulationyearly in sand green

1997 1998 1999

0.65% 6.0% 3.0%

USGA spec. green constructed in 1997 with 20% (by volume) organic matter

Green Age Effects on Microbial Biomass

Green Age Effects on Microbial StabilityRootzone accumulation

seasonal root growth

-180

-160

-140

-120

-100

-80

-60

-40

-20

0

sp

rin

g

su

mm

er

fall

win

ter

rootgrowth

2/22/2018

4

Thatch

A loose, intermingled, organic, layerof dead and living shoots, stems, androots that develops between the zoneof green vegetation and the soil

Greens Height Bentgrass Thatch Thickness (mm)

1

2

3

4

5

6

G-2 Southshore A-4 Penncross Providence SeasideData from Arizona NTEP Trial

Fairway Height Bentgrass Thatch Thickness (mm)

0123456789

G-2 Seaside II Cato Penncross Providence SeasideData from Ohio NTEP Trial

Benefits of “Moderate” Thatch

Improved resilience and cushion

improved wear tolerance

insulate soil/crown to temperature extremes

2/22/2018

5

Problems with excessive thatch

Footprinting


Scalping


LDS

Doug Soldat’s work at UW

Next 3 slides

Wetting agents, year differences and low and high OM greens

2009 – Wet Year – Low Organic Matter Putting Green

LSD0.05

=

2010 – Wet Year – Low Organic Matter Putting Green

LSD0.05

=

2/22/2018

6

2010 – Wet Year – High Organic Matter Putting Green

LSD0.05

=


Reduced Stress Tolerance


Overseeding Failure

Mat

Thatch that has been intermixed withmineral (soil) matter

Because of inherent ambiguity in terminologyand sampling techniques, the term “thatch-mat”has appeared frequently since the late 2000’s (McCarty et al., 2007; Barton et al., 2009;Fu et al., 2009).

. 3

2/22/2018

7

and yet one more definition…………..

SOM- Soil Organic Matter

Physical And Chemical Characteristics Of Aging

Golf Greens Roch Gaussoin, PhDJason LewisTy McClellanChas SchmidBob Shearman, PhD

This image cannot currently be displayed.

Treatments• rootzone Mix

– 80:20 (sand/peat)– 80:15:5 (sand/peat/soil)

• Grow-In Procedure– Accelerated– Controlled

2/22/2018

8

Project Schedule (Phase I)

1996 1997 1998 1999 2000

Data collection on soil physical, chemical, and microbial characteristics influenced by rootzone materials and grow-in procedures.

Greens construction ( one set per year)

Seeding

Project Schedule (Phase II)

2002 2003 2004 2005

Data collection on soil physical and chemical characteristics as influenced by age, rootzone materials and grow-in procedures.

13 yr oldgreen

9 yr oldgreen

Materials and Methods

10 yr oldgreen

12 yr oldgreen

As of 2009

0

10

20

30

40

50

60

70

80

90

100

-1 1 3 5 7 9 11

Age of Green (Years)

Infi

ltra

tio

n R

ate

(c

m h

r-1)

80:20

80:15:5

Expon. (80:15:5)

Expon. (80:20)

Data points and exponential regression lines of infiltration rate decline on USGA specification putting green

80

85

90

95

100

105

110

115

120

1 2 3 4 5 6 7 8 9


Per

cen

t o

f Y

ear

1 T

ota

l P

oro

sity

(%

)

Percent of Year 1 Total Porosity (80:20) = 99.1 - 0.6(Age)

r2 = 0.08Percent of Year 1 Total Porosity (80:15:5) = 101.7 - 0.6(Age)

No significant change in total porosity over time

50

60

70

80

90

100

110

120

130

140

150

1 2 3 4 5 6 7 8 9


Per

cen

t o

f Y

ear

1 A

ir-F

ille

d P

oro

sit

y (

%)

Percent of Year 1 Air-filled Porosity 80:20 = 100.8 - 3.8(Age)

r2 = 0.26Percent of Year 1 Air-filled Porosity 80:15:5 = 105.0 - 3.8(Age)

r2 = 0.26

Significant decrease in macro-porosity over time

2/22/2018

9

0

50

100

150

200

250

300

1 2 3 4 5 6 7 8 9


Per

cen

t o

f Y

ear

1 C

apil

lary

Po

rosi

ty (

%)

y = 91.5 + 8.1(Age)

r2 = 0.16

Significant increase in micro-porosity over timeFormation of Mat

• Formation of mat layer increased approximately 0.65 cm annually (following establishment year).

• No visible layering, only a transition is evident between mat and original rootzone.

• Topdressing program– Light, Frequent

• every 10-14 days (depending on growth) and combined with verticutting

– Heavy, Infrequent• 2x annually (spring/fall) and combined with core aerification

Green age (years)

8 7 6 5

Mat development (cm)2.8 2.5 2.2 2

Original Rootzone

Mat• 2004 USGA research

committee site visit

• original rootzone

• mat development

Materials and Methods

• 2004 rootzone samples taken below mat layer from each soil treatment and sent to Hummel labs for Quality Control Test (24 total samples) & tested against original quality control test (z-score).

• Other analysis also completed 0

5

10

15

20

25

in hr -1

Comparison of preconstruction Ksat values to Ksat values taken 10/04.

2/22/2018

10

Change in Rootzone Particle Size Distribution

• All rootzones tested in 2004 showed increased proportion of fine sand (0.15 – 0.25 mm) with decreased proportion of gravel (> 2.0 mm) and very coarse sand (2.0 – 1.0 mm).

• 5 of 8 rootzones were significant (z-score) for increased fine sand content.

0

5

10

15

20

25

30

35

2 mm 1 mm 0.5 mm 0.25 mm 0.15 mm 0.10 mm 0.05 mm

USGA Specification

Topdressing Sand

USGA sand specifications compared to sand used in topdressing program for USGA plots at Mead, NE.

%

Conclusions

• The KSAT decrease over time maybe due to organic matter accumulation above and in the original rootzone and/or the increased fine sand content originating from topdressing sand

Root Zone: Mat vs. Original

• pH:– Mat < Original for all USGA and California

Greens.

• CEC, OM, and all Nutrients tested:– Mat > Original for all USGA and California

Greens.

Want to know more?• Gaussoin, R., R. Shearman, L. Wit, T. McClellan, and J.

Lewis. 2007. Soil physical and chemical characteristics of aging golf greens. Golf Course Manage. 75(1):p. 161-165.

Why is high OM considered to be “bad”?

• Loss of infiltration

• Decreased aeration

• Traps “toxic” gases

• Are these concerns real or imagined?

• Why the confusion?

2/22/2018

11

Green Age (years)

4 3 2 1

Infiltration

all slides with the USGA logo in the corner are courtesy of Paul Vermeulen. Director, Competitions Agronomy at PGA TOUR, former USGA Agronomist

2.5 3.0 3.5 4.0 4.5 5.0 5.5

Low High

Organic Matter Recommendations

• Range

1.5 – 2.5% between 0.25 to 1-inches

8 – 15%

• Recommendations for almost every point in between

2.5 3.0 3.5 4.0 4.5 5.0 5.5

Low High

Adams: < 5%

J. W. Murphy: < 4.5%

McCoy: < 3.5%

Hartwiger & O’Brien: < 3.5 – 4.5%

Carrow: < 3%

Private Lab A: 1.5 – 2.5% at a 0.25 to 1-in depth

Lowe: < 3 - 4%

Private Lab B: < 3% - unrealistic< 4% - difficult< 5% - realistic & achievable

N.Z. Turf In.: < 8%

Sampling of Recommendations

Analysis Methods

• Many exist, but the most relevant is “combustion” or “loss on ignition”

• The sample represents both dead and living organic matter– Food for thought……

2.5 3.0 3.5 4.0 4.5 5.0 5.5

Organic Matter Sampling Protocols

1. thatch + mat layer 2. between 0.5” and 4.5” 3. between 0 and 35 cm 4. between 0 and 25 cm

Low High

2/22/2018

12

There is no “magic” number

“the squeeze test”(courtesy of Dave Oatis-USGA Director NE-US)

OM Testing

• Know how your sample was taken and compare notes with others that use the same protocol

• Take annual tests to determine long-term trend– Same time of year– Same location and green

• Correlate your test results with turf quality and performance during stressful environmental conditions to determine need for changes in management program

• Threshold/critical levels likely vary across the United States and from course to course

Seasonal Variation(One Location)

LSD = 0.175

1.85

1.90

1.95

2.00

2.05

2.10

2.15

2.20

2.25

2.30

2.35

Date Sampled

a

ab

b

JUNE

SEPT

DEC

How do you get rid of OM?

?????

2/22/2018

13

Organic Matter Degradation Study

2007

Treatments• Aerator (Granular)• Aerator (Liquid)• EXP072• EXP074• EXP076• Carbo-Plex• Bio-Blend• Carbo-Plex + Bio-Blend• Bio-Groundskeeper (Granular)• Bio-Groundskeeper (Liquid)• Thatch X• EXPO70M• EcoChem Lawn Thatch Reducer• Untreated Control

Locations

• KY Bluegrass Tee Box– Native Soil

• Bentgrass Green– California Green

• KY Bluegrass Sports Turf– Sand based

– 2.5” Mowing

Plot Set-Up14 Treatments, 3 Reps

Each Plot Aerified before Application of products

Data Collection

• Infiltration

• Penotrometer

• Thatch

• Organic Matter– Thatch, 0-3”, 3-6”

2/22/2018

14

Analysis Summary

Source Thatch

(mm)

Clegg

(g)

Infiltrat

(in/hr)

Thatch

(OM %)

0-3”

(OM %)

3-6”

(OM %)

Site ** * ** ** ** **Trtmnt NS NS NS NS NS NS

Site X

Trtmnt NS (0.10) NS NS * NS

0-3” OM %

0

1

2

3

4

5

6

7

Sports Turf Green Fairway

Summary

• No product increased degradation of OM

How effective is removal?

• Surface disruptive, short and long term

• Core aeration is the most widespread practice recommended for OM management

2/22/2018

15

Tine Size and Surface Area Chart

Tine Size (in.)

Spacing(in.)

Holes/ft2

Surface Area

of One Tine

Percent Surface

Area Affected

1/4 1.252 100 0.049 3.4%

1/4 2.52 25 0.049 0.9%

1/2 1.252 100 0.196 13.6%

1/2 2.52 25 0.196 3.4%

5/8 2.52 25 3.07 5.3%

3611

Organic Matter Management

• Funded by:– USGA (2006)

– Nebraska Golf Course Superintendents Assoc. (2007-2009)

– Golf Course Superintendents Assoc. of South Dakota (2006-2009)

– Peaks & Prairies GCSA (2007-2009)

Project Objective

National Survey

Determine cause and effect relationship among maintenance practices and their interactions relative to surface OM accumulation

Sampling Procedures Years 1, 2, & 3 At least 3 different greens per golf course

sampled Soil samples taken from 3 different area per

green Samples are evaluated for OM levels using LOI GPS location

Management & Site survey

2/22/2018

16

Sampling Methods

• Samples from at least 3 greens per course– (1) Problematic, (1) Non-problematic

plus rebuilt or varied age/management

• 3 samples from each green• Samples taken with

¾ inch soil probe

Verdure Layer Removed

3 inches

Sample Layer

2006/07/08 Samples

• Sixteen states– Nebraska, South Dakota, Iowa, Wyoming, Colorado,

Washington, Wisconsin, Illinois, New Jersey, Minnesota, New Mexico, Montana, Hawaii, California, Connecticut, Arkansas.

• 117 golf courses sampled– More than 1600 samples

WY

CO

SD

NE IL

WI

HI

MT

NM

WA ID

IANJ

MN

AR

CA

NY, CT

Problematic vs Non-problematic

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Good Average Bad

Superintendent predicted vs actual

0

1

2

3

4

5

6

7

8

Actual Predicted

2/22/2018

17

Green Age

Age

OM

%

0

1

2

3

4

5

6

7

8

9

0 20 40 60 80 100 120

Is the age effect misleading?

• Sampling issue:

– Mat depth increases as green ages resulting in more OM in the same volume soil.

8

8

88

7

77

7

6

66

6

5

55

5

0%

1%

2%

3%

4%

5%

6%

7%

8%

Thatch 0-2.5cm 2.5-10cm 10-20cmDepth

OM

(%

)

8 7 6 5

Organic Matter in USGA Specification Rootzones

Green Age (years)

a a a a

b b b b

c d e f

g g g g

LSD=0.05

8 7 6 5Green Age (years)

Mat Development with Age

NS

**

NSNS

State Differences(highly correlated with age)

State

OM

%

0

1

2

3

4

5

6

7

NE WA SD WY CO WI IL NJ IA MN MT NM CA CT AR

Cultivar

OM

%

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Unknown Penncross Providence Dominant Pennlinks L 93 A or G Series

2/22/2018

18

Cultivar

OM

%

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Unknown Penncross Providence Dominant Pennlinks L 93 A or G Series

Cultivation Frequency (& type)

OM

%

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Monthly 3-4 per year Spring and fall Spring only Fall only Every other year

Cultivation Frequency (& type)

OM

%

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Monthly 3-4 per year Spring and fall Spring only Fall only Every other year

Topdressing Frequency

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

1-2 Weeks Monthly Every other month Twice per year

OM

%

Topdressing

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0

OM

%

Topdressing rate (tons/1000 ft2)

Survey Summary

• None of the variables collected, by themselves, or in combination with others, predicted OM

• Courses using >18 cubic ft*/M of topdressing with or without “venting” consistently had the lowest OM

• Of the known cultivars, no differences in OM were evident

*1 ft3 = 100 lbs of dry sand; yd3 = 2700 lbs

2/22/2018

19

Onsite NTEP Cultivar Evaluation

1 L-932 Putter3 Cato4 Crenshaw5 LCB-1036 Penncross7 Backspin8 Trueline9 Providence

10 SR 102011 SR 1119 12 Viper13 Century14 Imperial15 Penn A-116 Penn A-417 Penn G-618 Penn G-1

Onsite NTEP Bentgrass Evaluation

Penncross Penn A-4 Crenshaw

“New ultra-dense varieties of bentgrass and bermudagrass are especially susceptible to

excessive organic matter accumulation due to high shoot density and the ability to grow a

deep, dense root system in sand-based rootzone material. Working topdressing into a tight canopy of turf is a challenge, and much

of the sand can be removed with the clippings.”

Vavrek, 2006

Topdressing and the new bents

Easy or hard???

2/22/2018

20

Penncross A4

L-93 Crenshaw

New bents = denser and more upright

Pulling cores or poking holes?

• In 2005, 45 of 141 courses surveyed* planned no core removal– Many had not pulled cores for 2-20 years

• 75 planned to pull cores– 35 of the 75 had no agronomic reason to pull a core (based

on USGA Agronomist evaluation) while 40 “needed” to pull cores

• With current and evolving cultivation/topdressing/ rootzone technologies is pulling a core always necessary?

• Finally, is core cultivation an effective way to manage OM ?

* Mid-continent region USGA

Let’s take a quick look at that…

Concrete/PVC placeholders Template with 0.5” diameter cores at 2.5” spacing

Cores removed to 5” depth; cores filled with sand topdressing

Modified soil probe simulates 0.5” diameter hollow-tine core aeration

Stabilizer block to ensure vertical probeentry

Bolts insert into placeholders to ensure exact location for resampling

2/22/2018

21

• Study initiated 22 June 2005; concluded 11 Nov. 2005

• 2 USGA Putting Greens– Constructed in 1997 and 2000

• Sample every 2 weeks for 20 weeks

• 2 depths of interest– 3 & 6”

Time after core creation (weeks)

2 4 6 8 10 12 14 16

PuttingGreen

DepthOrganic Matter Reduction (%)

9 yr 3” 79 73 70 71 69 66 67 66

6” 71 64 60 63 59 56 57 56

5 yr 3” 73 66 61 62 62 62 61 59

6” 66 56 51 51 52 52 51 49

Organic Matter Management Study

Objectives

1. Determine if conventional hollow tine is more effective than solid tine aerification at managing organic matter accumulation

Organic Matter Management Study

Objectives

1. Determine if conventional hollow tine is more effective than solid tine aerification at managing organic matter accumulation

2. Determine if venting (less invasive cultivation) methods are effective at managing OM accumulation

Treatments

Tine Treatment

None

2X Hollow tine

2x Solid tine

Venting Treatment

None

PlanetAir

Hydroject

Bayonet tine

Needle tine

15 Trts per Rep

6 Reps per year

2 different years

= A whole lot of fun for one graduate student or 180 trts

2/22/2018

22

All treatments received the same topdressing quantity (22 ft3/M) but different frequency

Regional Survey

• Annual topdressing rate for 10 well maintained courses in each region

– Stable maintenance program during past 5 growing seasons

– Same general turf conditions

• Surveys are not research!

– Fertility

– Traffic

– Green construction

– Etc.

Survey Anticipated Results

• Cool-season - gradual increase in annual topdressing rate from north to south and east to west corresponding to length of growing season

• Warm-season – changes in annual topdressing rate corresponding to overseeding practices, length of growing season, annual rainfall

• Surveys are not research! fertility traffic green construction etc.

Survey Expectations

• Cool-season - gradual increase in annual topdressing rate from north to south and east to west corresponding to length of growing season

• Warm-season – changes in annual topdressing rate corresponding to overseeding practices, length of growing season, annual rainfall

• Surveys are not research! fertility traffic green construction etc.

Mid-Continent, Carrollton, TX

Topdressing (ft3/1,000ft2/yr)Mean: 0Range: 0Standard Deviation: 0

North-Central, Elm Grove, WI

Topdressing (ft3/1,000ft2/yr)Mean: 20.7Range: 8.4 – 34.5Standard Deviation: 8.2

Mid-Continent, White Heath, IL


North-Central, Covington, KY


Central United States – Cool-season










2/22/2018

23

Empirical Rule

68% of measurements are within plus or minus one standard deviation (s) of the mean (y)

s

y

s










Southeast, Griffin, GA


Northeast, Palmer, MA & Easton, PA


Mid-Atlantic, Glen Mills, PA


Mid-Atlantic, Pittsburgh, PA


Eastern United States – Cool-season

Northwest, Gig Harbor, WA


Northwest, Twin Falls, IDTopdressing (ft3/1,000ft2/yr)

Mean: 24.7Range: 5.3 – 43.1Standard Deviation: 11.5

Southwest, Santa Ana, CA


Western United States – Cool-season

Florida, Rotonda West, FL


Southern United States – Warm-seasonSoutheast, Birmingham, AL

Topdressing (ft3/1,000 ft2/yr)Mean: 0Range: 0Standard Deviation 0

Florida, Hob Sound, FL

Topdressing (ft3/1,000 ft2/yr)Mean: 0Range: 0Standard Deviation 0

Southwest, Santa Ana, CA

Topdressing (ft3/1,000 ft2/yr)Mean: 24.1Range: 11.4 – 33.7Standard Deviation 12.0


Topdressing (ft3/1,000 ft2/yr)Mean: 38.0Range: 22.3 – 85.5Standard Deviation 17.3

Region/Turf Ave. Rateft3/1,000ft2/yr

Rangeft3/1,000ft2/yr

Sample Standard Deviation

Florida – Upper / ultradwarf, overseeded

Florida – Lower / ultradwarf, non-overseeded 90.2 62.9 – 147.6 36.6

Mid-Atlantic - Eastern / cool-season 15.8 7.5 – 26.3 6.7

Mid-Atlantic – Western / cool-season 27.1 16.2 – 51.1 11.1

Mid-Continent – Lower / cool-season

Mid-Continent – Lower / ultradwarf, non-overseeded 38.1 22.3 – 85.5 17.3

Mid-Continent – Upper / cool-season 20.8 15.8 – 30.6 4.5

North-Central – Upper / cool-season 20.7 8.4 – 34.5 8.2

North-Central– Lower / cool-season 18.5 8.3 – 25.4 7.62

Northeast / cool-season 20.3 12.0 – 51.7 8.8

Northwest - Coastal / cool-season 31.6 22.5 – 39.4 5.8

Northwest - Inland Northern Rockies / cool-season 24.7 5.3 – 43.1 11.5

Southeast – Lower / ultradwarf, non-overseeded

Southeast – Upper / cool-season

Southwest - Coastal California / cool-season 38.0 10.7 – 70.3 23.8

Southwest - Desert / warm-season, overseeded 24.1 11.4 – 33.7 12.0

Regional Topdressing Survey Summary

2/22/2018

24

Survey Review

• Regional differences were found, however not exactly as predicted

• Some differences did not appear to have a basis in agronomy or climatic conditions

• Survey results generate multiple questions regarding current industry practices and suggest need to conduct further research in the area of organic matter management

• It is premature to conclude that the survey provides guidance for establishing sound topdressing recommendations due to the broad range of the data and the very high standard deviation found in most regions

All treatments received the same topdressing quantity (22 ft3/M) but different frequency

Equilibrated to identify differencesof the practices in question

Materials and Methods• Green Age:

– 12 years

– 9 years

• Data collected:– OM% (pre-cultivation/monthly)

– Single wall infiltration (monthly)

Infiltration (in/hr)

0

5

10

15

20

25

CORE NONE SOLID

NONE

PLANET-AIR

HYDROJECT

BAYONET

NEEDLE

A

A

BB

B

BB

B

BB

B

A

A

A

A

Relationship between OM and Infiltration

*Significant at α = 0.01

OM

%

OM Data Analysis Year 1

• No differences between green age except for higher % in older green

2/22/2018

25



• No differences among venting methods




• No interactions with solid/hollow/none

Effect of Aerification on OM

2

2.1

2.2

2.3

2.4

2.5

None Core Solid

A

BB










2/22/2018

26





• No differences among solid/hollow/none

Effect of Aerification on OM

2

2.1

2.2

2.3

2.4

2.5

None Core Solid

What these data do/don’t suggest

• Topdressing is the most consistent and repeatable factor in OM management

• Cultivation was insignificant as a means to control OM

• However, a superintendent must use whatever tools they have at their disposal to insure sand is making it into the profile and not the mower buckets

Topdressing interval relative to Tine/LIC combinations (22 cu ft/M)*

• NONE/NONE– 5-10 days

• Solid & Hollow/NONE– 7-14 days

• Solid & Hollow/LIC– 14-18 days

*Observed and calculated based on displacement and surface area opened

GreenKeeper Surveycool season only, mark all that apply

In the last 5‐10 years, on our greens, our facility has:

Increased topdressing quantity.

Increased topdressing frequency.

Increased hollow (equal or greater than 0.5") tine aeration.

Increased solid tine (equal or greater than 0.5") aeration.

Decreased hollow (equal or greater than 0.5") tine aeration.

Decreased solid tine (equal or greater than 0.5") aeration.

Made minimal changes in topdressing application quantity/frequency.

Made minimal changes in cultivation practices.

Increased "venting" practices.

2/22/2018

27

Survey Respondents via Greenkeeper

303 Responses

^Venting

^ TD Freq

^TD Quant

^Solid

Dec Hollow

^ Hollow

Min TD

Min Cult

Dec Solid

0 50 100 150 200 250

“the solution to pollutionis dilution”

TopdressingOld Tom Morris (1821–1908) is

thought to have discovered the benefits of topdressing accidentally when he spilled a wheelbarrow of sand on a putting green and noted how the turf thrived shortly afterward (Hurdzan, 2004).

J.B. Beard is his classic textbook“Turfgrass Science & Culture, 1973writes:“The most important managementpractice for OM managementis topdressing”

What is the “best” way to get sand into the profile?

Layering

Water retention is non-uniform

Thatch/mat layers can store twice as much water than the root zone

NOT a functionof drainage

Rather it is thedifference in pore

size distributionamong layers

2/22/2018

28

Layering

Aeration alone not that effective

Must topdress to dilute OM (change its pore size distribution) and use deficit irrigation

“the solution to pollutionis dilution” Soil Macropores

Compacted

2/22/2018

29

2/22/2018

30

How do you get rid of OM?

• Decomposition (microbial)– Increase surface area and aeration

– Inoculation

• Removal– Power raking, dethatching, core aerification

• Dilution– Topdressing

Acknowledgements• USGA • Environmental Institute

for Golf

• Nebraska GCSA

• GCSA of South Dakota• Peaks & Prairies GCSA

• Jacobsen, Toro, JRM & PlanetAir

• Nebraska Turfgrass Association

Documents

ASA Monograph (3RD Edition) Chapter 12 · 13 yr old green 9 yr old green Materials and Methods 10 yr old green 12 yr old green As of 2009 0 10 20 30 40 50 60 70 80 90 100-1 1 357